Disclaimer: Ideas in this work may or may not be the same as my current or previous employers and or colleagues. Most of the ideas here are not my invention and are either widely accepted pieces of knowledge or are part of referenced literature in the end. Major influence on work is from the book by Dougles Hubbart: How to measure anything. I just humbly synthesized these ideas to more condense form in hope that it will help future game creators. I hope that you will have “fun” and if so, please write me your opinions on [email protected], or as a comment here.

Is this game fun? I don't know, I don't care.

I mean, I kinda care, otherwise I would not write about it. Nevertheless, there exist many theories and definitions of fun, and each of them is failing on one or another front. Good news is that we don't have to know what fun is. How many of you actually know what kilogram really is? It used to be a weight of one liter of water, that times are long gone. Nevertheless, we still use kilogram to weight objects around us. If I tell you that the object’s weight is 500 kg you will probably imagine something of car-size. If I tell you that I lost 20 kilograms, you would see it as a big weight loss. We don't need to know what exactly something is to use it in measurements. We just need to know how a kilogram (or in our case "fun") manifests in the world. This is especially true about intangible things like opinion, religion, happiness, love, anger, health and fun. Intangibility never stopped us, why it should in case of fun?

Now, considering not only what fun is, but how it actually manifests in the world; somebody can say “I have fun when I try something several times, before I get it right, I feel challenged that way.” or somebody may frown, grip the controller very tightly while retrying the same passage for several minutes; is any of this fun? I don’t know, but I know that in my game part of fun should be being challenged and this seems like players are being challenged. Things that are happening in the world like players actions or players expressions, that we can observe and therefore measure are called proxies. They are not directly thing that we are interested in but, they show us the right way to it

We don’t need to know precisely what x is to measure it. We need to know how x manifests in the world so we have proxies to measure. 

Scientific method for dummies

First, a quick detour to school. Why are we going to stand on scale in the first place? We have some internal (folk) theory of how our weight is connected to our physical condition. Kilograms within a specific range means healthy, outside of it means unhealthy.

We as humans have tons of such theories about everything around us. We have internal theories (sometimes called mental model) describing why objects fall to the ground or why our friend behaves a certain way. Thanks to these theories we can predict that will happen if we throw a ball in the air and tell our friend to catch it. 

Theories are clusters of hypotheses that should be coherent with each other. A hypothesis is an explanation of how x is connected to y. If x happens then y should always react the same to that event. Hypotheses in theories are interconnected; that means that if we know what is the relationship between x and y and we also know what is the relationship between y and z, then we should be able to deduce the relationship between x and z. 

Cases in which we know truly what the relationship between x and y are very rare. In practice more often than not we are not trying to get a true relationship but as close to true as possible. Closer to this case we are, the better hypothesis we have. By getting better hypotheses we are getting better theories. If the hypothesis is not good enough we scratch it and come up with a new one. A hypothesis that does not improve our theory is not good enough. Once our hypothesis is good enough (or better than starting one) we update our theory. Once we have updated theory we can set up a new better hypothesis based on it, and then the whole loop starts again. With internal theories, we do this automatically and unknowingly (simplified base for learning). Once we make it explicit we can do it way more effectively and generally better. That is a very simplified core of the scientific method. When we are inquiring about the connection of our proxies and “fun” we are using very same core principles. We as game creators to this all the time, so I think it is time to take the next step and make it explicit.

How can we do this next step? Well first we have to set up our hypothesis and then we have to measure it! This is the end of the detour, now we can look at proxies that helps us with measuring.

Using proxies

When we stand on a scale, information that we receive is a number. Do we really care for the number or do we care for the idea that this number represents - in case of a scale it is our health. Essentially, Measurement is an approximation of one phenomenon to another, till we get to an approximation that we understand intuitively (or rather something that is already part of our internal theory). That is the power of proxy. Proxy is a phenomena about which we have enough intuitive understanding. Yes, different people can have a different intuitive understanding of the same topic. Junior designers would argue about who is right, experienced designers would set up an experiment for their theories and then measure the outcomes. 

A great theory with bad measurements will lead to worse results than a weak theory with great measurements. Bad measurements will improve theory only a bit (if at all) while good measurement can move theory by miles (this is iteration once again, you probably heard of that before). How do we know measurements to choose? Measurements have parameters:

For sure you can imagine, that each measurement can have different degrees of each parameter. Imprecise but accurate weight will show +/- 25% of the real value each time you step on it. Scale with rough granularity will show only kilograms and precise but inaccurate weight will show exact numbers each time but it will be exactly 8 kilograms off. In each case you will not know exactly what you wanted to know but you will be closer to the truth than before. 

So why not always have as precise, as accurate and as granular measurement as possible? Well, because it is expensive; in terms of money, time and actual know-how. Measuring salt for your home cook dinner will be very different than measuring salt for royal wedding main course by a professional chef. Different situations require very different degree of measurements. This all depends on the decision that you are making. 

Measurement is all about decisions

Design is a sequence of decisions about what to make and what not to make. To make this decision we need to have a theory about how each part of our designed game works and what experience it induces. To have the best possible theory we have to improve it as much as possible, and to improve it we have to have as many as good measurements as it is possible. Best designers are not one, who think they know how things should be, but those who are able to update their theory as fast as possible (and this is basically iteration on design).  

Every singular decision is connected to a specific subset of hypotheses in theory. These are usually hypotheses regarding proxies or approximate to the proxies we use. Closer the proxies are to our question stronger connection they have. Therefore to make decision we should measure and explore the closest proxies. For example: What you eat and how much you move is closer to your health than fuel consumption of a bus in your city. Nevertheless, both are part of an energy transformation theory. Hence learning about the combustion system may help us with our diet, learning about calories will help us way more.

As you can see, closer the connection more value we get from our investment. You should never invest more resources into measurements than you will get from it. What value you can get from investing in measurement? Well main candidates would be faster iterations, lowering opportunity cost, evading retroactive fixing, evading out of scope or under scope features, more effective testing.    

Beware the noise

One of the most dangerous parts of collecting data is over-analyzing and over collecting them. I have seen many developers do this. Do you think you didn't? When was the last time you went through Reddit or steam reviews and then came back to the office with a whole new idea about what should you change? This is also the case of that. Humans are pattern making machines. We see faces in clouds, moods in yellow circles with dots and patterns where there are none. Sometimes you can have too much data for your own good, especially if data are not accurate or precise. To lower the chance of the noise talking you should always strive to refutability by looking for counter examples and corroborate by employing multiple different kind of measurements.

But I don’t have a data scientist!

...and you don't really need one (but they are extremely useful and I love all of them). It is about properly set parameters of measurement again. Analyst will offer you quite precise and accurate data. No measurement at all will offer you precisely and accurately no data. There is vast space between these two points where you can operate quite cheaply and fast.

Here are some examples of measurements in various degrees. I will always add advanced and minimal variant examples. I doubt that you will use the advanced variant anytime soon, but that is ok. Also take notice that it is just a simple summarization of a few methods, it should serve more as inspiration for additional research than exhaustive list.

Heuristics:

With this method we are looking for rules of thumb. Some very simple rules that may lead to specific consequences. This is domain of “player type” of game creators and seniors who played it all already. Short Heuristic analysis can reveal a lot even before you start the game. Good news is that you probably already do this, just not systematically. For example: Does this platformer have a coyote time and how far? Does healing potion have the same colour as health (probably red)? It is well known approach in service and product design (try to ask your closest UX designer).  

Playtest: 

Playing games and seeing how it works. What happens in the game. It is basically starting the whole thing and seeing it running. There are a lot of very good articles, Reddit posts and videos on how to playtest for good reason. Playtesting is the cornerstone of any game development. If you are not doing this already then I don't know what you are doing.